Attention seems to play an important role in the ability of a listener to extract information from a complex environment. The first hypothesis to be tested is that auditory tasks performed in a complex environment require more attentional resources than in a simple environment. This will be tested by measuring the ability of listeners to perform one or more tasks in the presence of interfering sounds. By using the dual-task methodology, the costs of dividing attention between tasks will be quantified. The second hypothesis is that hearing impaired listeners must devote more attentional resources to equivalent auditory tasks - simple or complex - than must normal hearing listeners. A number of researchers have concluded, based on their research, that listeners with sensory-neural hearing loss have deficits that go beyond degraded sensory representations. If a normal hearing listener can perform a particular task with a given amount of attentional resources, it is possible that the amount of resources required for impaired listeners to do the same task is greater, in an amount correlated with the degree of hearing loss. By again employing the dual-task, the attentional resources used by hearing-impaired listeners will be compared with those used by normal-hearing listeners in the same tasks.